Matches a Future that completes succesfully with a value that matches
matcher.
Note that this creates an asynchronous expectation. The call to
expect() that includes this will return immediately and execution will
continue. Later, when the future completes, the actual expectation will run.
To test that a Future completes with an exception, you can use throws and throwsA.
The description parameter is deprecated and shouldn't be used.
Source
Matcher completion(matcher, [@deprecated String description]) =>
new _Completes(wrapMatcher(matcher));